Isolation Example

Accumulo has an isolated scanner that ensures partial changes to rows are not
seen. Isolation is documented in ../docs/isolation.html and the user manual.

InterferenceTest is a simple example that shows the effects of scanning with
and without isolation. This program starts two threads. One threads
continually upates all of the values in a row to be the same thing, but
different from what it used to be. The other thread continually scans the
table and checks that all values in a row are the same. Without isolation the
scanning thread will sometimes see different values, which is the result of
reading the row at the same time a mutation is changing the row.

Below, Interference Test is run without isolation enabled for 5000 iterations
and it reports problems.